How to use

CommandSubscription

in

org.eclipse.hono.client

/**
 * Creates a command subscription object for the given topic. When the authenticated device is given
 * it is used to either check given tenant and device-id from topic or fill this
 * fields if not given.
 *
 * @param topic The topic to subscribe for commands.
 * @param authenticatedDevice The authenticated device or {@code null}.
 * @return The CommandSubscription object or {@code null} if the topic does not match the rules.
 * @throws NullPointerException if topic is {@code null}.
 */
public static CommandSubscription fromTopic(final String topic, final Device authenticatedDevice) {
  try {
    return new CommandSubscription(topic, authenticatedDevice);
  } catch (final IllegalArgumentException e) {
    LOG.debug(e.getMessage());
    return null;
  }
}

String tenantId = subscription.getTenant();
String deviceId = subscription.getDeviceId();
if (subscription.isAuthenticated()) {
final String topic = String.format("%s/%s/%s/%s/%s/%s", subscription.getEndpoint(), tenantId, deviceId,
    subscription.getRequestPart(), commandRequestId, command.getName());
endpoint.publish(topic, command.getPayload(), qos, false, false);
metrics.incrementCommandDeliveredToDevice(subscription.getTenant());
LOG.trace("command published to device [tenant-id: {}, device-id: {}, MQTT client-id: {}]",
    subscription.getTenant(), subscription.getDeviceId(), endpoint.clientIdentifier());
final Map<String, String> items = new HashMap<>(3);
items.put(Fields.EVENT, "command published to device");

final CommandSubscription cmdSub = CommandSubscription.fromTopic(subscription.topicName(), authenticatedDevice);
if (cmdSub == null) {
  span.log(String.format("ignoring unsupported topic filter [%s]", subscription.topicName()));
      sendDisconnectedTtdEvent(cmdSub.getTenant(), cmdSub.getDeviceId(), authenticatedDevice, null)
      .setHandler(sendAttempt -> {
        consumer.close(null);
    span.log(items);
    LOG.debug("created subscription [tenant: {}, device: {}, filter: {}, requested QoS: {}, granted QoS: {}]",
        cmdSub.getTenant(), cmdSub.getDeviceId(), subscription.topicName(),
        subscription.qualityOfService(), MqttQoS.AT_MOST_ONCE);
    return cmdSub;
    TracingHelper.logError(span, items);
    LOG.debug("cannot create subscription [tenant: {}, device: {}, filter: {}, requested QoS: {}]",
        cmdSub.getTenant(), cmdSub.getDeviceId(), subscription.topicName(),
        subscription.qualityOfService(), t);
    return Future.failedFuture(t);
if (f.succeeded() && f.result() instanceof CommandSubscription) {
  final CommandSubscription s = (CommandSubscription) f.result();
  sendConnectedTtdEvent(s.getTenant(), s.getDeviceId(), authenticatedDevice, span.context());

private Future<MessageConsumer> createCommandConsumer(final MqttEndpoint mqttEndpoint, final CommandSubscription sub) {
  // if a device does not specify a keep alive in its CONNECT packet then
  // the default value of the CommandConnection will be used
  final long livenessCheckInterval = mqttEndpoint.keepAliveTimeSeconds() * 1000 / 2;
  return getCommandConnection().createCommandConsumer(
      sub.getTenant(),
      sub.getDeviceId(),
      commandContext -> {
        Tags.COMPONENT.set(commandContext.getCurrentSpan(), getTypeName());
        final Command command = commandContext.getCommand();
        if (command.isValid()) {
          onCommandReceived(mqttEndpoint, sub, commandContext);
        } else {
          // issue credit so that application(s) can send the next command
          commandContext.reject(new ErrorCondition(Constants.AMQP_BAD_REQUEST, "malformed command message"), 1);
        }
      },
      remoteClose -> {},
      livenessCheckInterval);
}

final CommandSubscription cmdSub = CommandSubscription.fromTopic(topic, authenticatedDevice);
if (cmdSub == null) {
  final Map<String, Object> items = new HashMap<>(2);
  LOG.debug("ignoring unsubscribe request for unsupported topic filter [{}]", topic);
} else {
  final String tenantId = cmdSub.getTenant();
  final String deviceId = cmdSub.getDeviceId();
  final Map<String, Object> items = new HashMap<>(2);
  items.put(Fields.EVENT, "unsubscribing device from topic");